The primate follicle and corpus luteum play key roles in the production of a mature oocyte, modulation of oviductal/uterine environment via steroid production and the successful establishment and maintenance of pregnancy. Studies examining the processes which direct the growth and differentiation of these tissues are limited due to technical difficulties, availability of primate ovaries, and the expense of conducting studies in primates. The objective of this study is to develop methods to transplant macaque ovarian tissues into the immunodeficient (SCID) mouse to create an experimental model for studying primate folliculogenesis and luteal development. Macaque ovarian tissues (n=2) were collected at ovariectomy or were provided by the Tissue Distribution Program following necropsy. Ovaries were placed in Ham's F10 medium at 4xC and transported to the laboratory, where the ovarian cortex was cut into cubes 1 x 1 x 0.5 mm for grafting under the kidney capsule and subdermally in mice. Mice were anesthetized, ovariectomized and the left kidney exteriorized via a flank incision. Ovarian cubes were inserted under the renal capsule with watchmaker forceps; several cubes were also placed in a subdermal pocket created under the skin. The incisions were closed with suture and Michel clips. Additionally, some mice received human FSH and LH following tissue implantation. Ovarian transplants were examined histologically after 3, 7, 14, 28, 56 and 90 days. Vascularization of the ovarian transplants under the kidney capsule occurred in 75% of the recipient mice. In these ovarian grafts, primary follicles (i.e., oocyte plus a single layer of granulosa cell) and several secondary follicles (multiple granulosa cell layers) were observed on days 3-28 after implantation. Mice with grafts for greater than 28 days and that received human gonadotropin treatment contained no visible oocytes. Additionally, ovarian tissue appeared to undergo a progressive replacement with scar tissue as the time from implantation increased. In contrast, control mouse ovaries that were placed under the kidney capsule underwent complete folliculogenesis and luteinization following transplantation. Further studies are needed to determine if the ovarian grafting procedure is a viable method for studying early follicular development in primates.